Turbojet engines and turbopumps have employed diffusers, in their conventional sense, aft of compressor and impeller stages, as well as aft of a turbine stage. In the former instance, a diffuser is necessary to disperse the molecules of compressed fluid (air) prior to induction of fuel. In the latter, it is often advisable to disperse the exhaust product after it has passed the turbine (output) stage.
Notwithstanding the dispersing effects of the diffuser, a great deal of compression action (or in the case of a hydro vapor engine, liquid fluid restriction) may be obtained by designing diffuser members so that the forward or upstream end will cooperate, through interactive geometry, with intake and combustion chamber surfaces, to restrict passage of the working fluid. Thus, if the working fluid is gaseous, it will be compressed upon passing the forward portion of a compressor diffuser and before exiting through the turbine. In actuality, these compression portions of the engine are usually of fixed shape and have rarely been considered as meriting design for variability in operation.
An exception to the foregoing general statement is found in the prior art and most often characterized as attempts to vary inlet flow characteristics of ram-and turbojet engines by either reshaping the inlet surfaces or moving a plug, nose cone or spike a short distance forward or aft of some index within the engine. That such devices, forward of compressor stages only, would perform their function is not argued herein; but what I feel is novel about my invention is a design of impeller/compressor/turbine in combination with a moveable diffuser, in a single engine or pump member. To my knowledge, acquired from conducting exhaustive literature searches and reading myriad patents, this combination has never been suggested nor attempted.
Save for rare attempts to combine both compression and dispersion characteristics, by altering engine interior surfaces or by the suggestion of a movable plug (for the ramjet), no hint or a singular device--in the turbojet or turbopump--has appeared. This more than likely derives from the fact that, in every case of turbine design, the blades of compressors, impellers, turbines, etc. are mounted to a body, a sizable portion of which serves as a compression or restriction feature working in cooperation with the interior, constrictive engine surfaces.
Having pointed out the complete lack of prior art and inventions in the subject area, it is intuitive that an object of this invention should be to provide a jet engine member that can function as a movable impeller/compressor-diffuser.
It is another object of this invention to provide a impeller/compressor-diffuser design which can function with blade members such as characterize turbines, pump impellers, compressors, etc.
It is another object of this invention to provide a means which will easily translate the compressor-diffuser for and aft along the turbine shaft.
I have designed an impeller-diffuser member to be used in my patented Hydrovapor Free Turbine Engine (U.S. Pat. No. 4,578,943). Such a device is preferably embodied as a shaft-borne body which bears a plurality of propeller blades about its periphery. One versed in the art will recognize that such a use can be employed in air breathing engines of the turbojet/turbofan class. For the remainder of this paper, I shall discuss the impeller/compressor-diffuser in combination with propeller mechanisms and in a liquid working fluid environment. It must be understood that similar, partial or complete applications can be made to air breathing turbojet engines. In an earlier work, it was hypothesized that, for most air breathing jet propulsion engines, there exists a hydro or water analog (see "State of the Art: Propulsion" by Victor de Biasi, Space/Aeronautics, Jan. 1960). For this particular application, the converse of that generalization will apply equally.
The objects and advantages of this invention are set forth herein and will either be obvious herefrom or may be learned by practice with the invention.